Anti-inflammatory effect of volatile oil from Schizonepeta tenuifolia on carrageenin-induced pleurisy in rats and its application to study of appropriate harvesting time coupled with multi-attribute comprehensive index method

Ethnopharmacological relevanceSchizonepeta tenuifolia Briq. (ST) herbs have been used as a Traditional Chinese Medicine (TCM) for treating colds for thousands of years. The volatile oil is considered as the main material basis responsible for the efficacy of ST and has attracted lots of attention on its anti-inflammatory effect recently.Aim of studyThis paper investigated the anti-inflammatory effects of the distilled volatile oils from Schizonepeta tenuifolia (STVO) that were collected at different harvesting times on carrageenin-induced pleurisy in rats. Based on the anti-inflammatory effects, instead of contents of marker components, we aim to evaluate the quality and determine the appropriate harvesting time of ST.Materials and methodsThere were eleven groups with eight male rats in each randomly. They were model group, control group, positive group (dexamethasone) and eight groups treated with eight STVOs at different harvesting times. All treatments were performed by gavage and administered once a day on four consecutive days. One hour after the last treatments, except the rats in control group, those in other groups were treated with carrageenin to induce the pleurisy. Four hours later, all the rats were sacrificed and their pleurisy exudates and lung tissues were collected for further analysis. To evaluate the comprehensive anti-inflammatory effect of the eight STVOs, multi-attribute comprehensive index method (MACIM) was used to obtain the integration of various effects.ResultsAll the eight STVOs could decrease the seven indicators relating to pleurisy, which were exudate volume, leukocytes, protein level, myeloperoxidase (MPO), malondialdehyde (MDA), tumor necrosis factor-α (TNF-α) and interleukine-1β (IL-1β). Majority of these decreases were significant (P<0.01, P<0.05). As far as each indicator was concerned, each STVO showed different effect from others. With MACIM, it was found that STVO in Group 6 was the most effective one with the highest Vs and appropriate harvesting time of ST was in late September.ConclusionsThe study may provide scientific basis to further understanding of the mechanism of STVO in anti-inflammatory effect of carrageenin-induced pleurisy. Meanwhile, this study also provides a new access to determining the appropriate harvesting time of TCM and even evaluating the quality of TCM.

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